Evaporator



T. M. PUSEY.;

, EVAPORATOR.l APPLICATION FILED SEPT. 18, 1919'.

2 vsHEETs-sHEm 1.

Patented' Mar. 8, 1921.

2 SHEETS-SHEET 2.

WIT/VE SSFS,

Arrow/'frs UNi'rEDl Be it knoivnthat l, THoMashM. a citizen ot theUnited States, and a resident i of Kennetty Square. in thecountyofClhester andy State ot Pennsylvania, vhave invented a n'e'iv andtlinproved Evaporator, of which the tollo'vving,is a description.rv

My invention y relatesl to evaporators and y more particularly to anapparatus orevapy oratiiig water out of zinc-chlorid or out of acid oralkali solutions or the line.

Bv the usual methods infe-vaporating water out ofa zinc-chlorid solutionfor exheat tothe evaporating process in a second or niain evaporator.

Again, zinc-chlorid solutions attack. the

metal of the eva'porating vessel and produce sinall punctures in most ofthe ordinary lmetals ot which vthe evaporators are made, thereby in'time causing the vessel to. leak.

My inventioirhas fory an important objectl to provide aiiyevaporator orvacuum kettle' in which to evaporate a solution of zinc.

fchlorid or other solutions containing acid or allfr'ali liable toattack the metal of the kettle and vvliiehfwillA evaporate in a partialvacuum and at la temperature below that of steam at atmospheric"pressureto thereby furnish an evaporator vvhich can utilize exhaust steamJf'roin steam engines or steam at atmospheric pressure which comes froma 4primary evaporator hereinafter referred to, or toutilize exhauststeam from any other convenient apparatus at or near atmosphericpressure. or yutilize hot Water.

Y A fiirtlier object of the invention is to provide an evaporator orvacuum kettle of the indicated character equipped Withlv a steamljaeketso that a body ot' steam at atmospheric pressure, when theapparatus is in operation, will surround the kettle except at the portlights `or windows, the arrangement being such that the steam Jfurnishesheat to evaporate the water out ofthe solution contained in the kettleand at the same Speceat-in of Letters Patent.

applicati@ meid sep/tenter is', i919'. serialY ii'jsziliesg, i i i I'rtiiiielacts asia Aseal tol' preyent 'jai'r roinleak- Ing into `theJvacuumh kettleI Athrough#v any i punctures therein and which wouldresult in a breaking or lessening of the valiuum, the

advantage beingthatJ steam enteringlthe kett'le insteady ot ain-Will do:very 'much vless dairiagev to the'l v'lueo'f the'y'acuum'than would becausedl by thesanie volume Ior amount'y otair', as it is al vyell knownNiact that a giveii volume or' aA given weight .lof vMair in a highvacuum is many times harder to remove than'the same volume or weightoflsteain in the "samefvac'uumy or in other ivor'ds. a" conde'r'iserot`a gi'if'eii size or capac- I ity ivill yreir'i'ove from a hig'lia'aciiumunder (erta'in coii'ditioiis,`one hundred, and, sometimes yseveralhundred times, the weight yor y v`ol`un'i'e of Isteam thatthe samelcondenser v.would reinove in iveight or volume ot air under the samelorlike conditionsl A y The inver'ition also has for an lobject ton-ovide'anevaporator' having an inside par titioii or .sleeve vvithinthe vacuuml kettle, thereby yproducing` a double Wall and forming anan'nular'fcliani'ber betiieen the `walls` lthe purpos' 'being to .causetliesolution fof zi'n'c-clil'orid to circulate and to preventun- 'evenorsudd'enl foaming in; the main mass ofthe zinclehlorid as ivell as toexpedite 'the evaporation'. ,1" further object of the invention i's vtoprovide 'anevapoat'orA having a'heating' coil "lie'neath thevz'icui'im'kettl'eand' so arranged as 'to 'utilize the l'ieatof' thevvat'e'r of'con-v dieated `character in' which provision is made forfacilitating the vremoval "ofthe kettle f and loth'er partsavhen'desired, for `linspection of parts, orf'tor the closing of anypun'ct'ures produced in the kettle by the material. treated' orthemaking of any 'other :necessarygr'epairs. y y l f The above and otherob]eets as will appear are attained by the: novel evaporator andappurtenances hereinafter lparticularly vde-l scribed' and defined'intheelaims.

Reference is to be had to the accompanying ,drawings l forming apart ofthis specification, it beingunderstood that the drawings' are merelyillustrativel of one example of the invention.

Figure l is a longitudinal vertical section of an evaporating apparatusembodying my invention;

Fig. 2 is a partly sectional plan vievv as indicated by the line -2-2,Fig. In carrying out my invention 1n accordance with the illustratedexanip e, a suitable hereinafter supporting structure or base 10 isprovidedon which is a tub 11, Removably supported tive arrangement ofthe 'kettle and tank 12 is such as to provide a substantial steam spaceentirely surrounding the kettle as further referred to.

j haust pipe 15 rises from the top of the kettle '14 and connects in vpractice with any pump or condenser (not shown) adapted to exi haust theair and steam from Y'the kettle. A

vent pipe 16 leads into the pipe 15 and has a valve 16 adapted toexclude air from the exhaust pipe or admit air thereto to break thevacuum, if desired, in removing the solutionvfrom the kettle after theevaporating process has been completed, as hereinafter referred to. .The top 13 of tank 12 has Windows'or port lights 17 fitted in tubularclosures 18 extending between the tank top 13 and the kettle top 14b sothat an electric lamp or any other'source of light may be suspendedabove one of said Windows that observation of the interior 'of thekettle may be m'ade through the other of said windows. a v

' Fora'portion of its height the kettle 14 has double Walls, there beinga partition 19 extending about the exterior from near the bottom thereofto near the top forming an annular space. which is in communica-- tionwith the interior of the kettle through the series of openings 20, saidpartition being supported in any suitable manner, there being shown aledge or ring l21 therefor within the kettle. Some or all holes 20- arecontrolled b'y-valves 22. the stems 28 of which extend through stuingboxes 24 on kettle 14 and tank 12, and provided with hand wheels orother operating handles 23a. The total capacity of the openings 2Oapproximately regulates the flow from the interior of the kettle totheannular chamber between the partition 19 and the outer Wall of thekettle and the capacity is regu- `the material of -strip 26 secured Thee .let 2T which in the the kettle lated closely by the valves 22 'atcertain ofthe openings. y, i

In order to make fluid-tight the riveted joints between the body ofthe'kettle 14 and 4the top and bottom thereof, a liquid seal is joints,said trough being adapted to hold any suitable sealing, filling orimpregnating substance that will prevent ingress of air or steam.Similarly, a liquidseal is provided extending vertically over thevertical joint 14c (see Fig. 2) of the overlapped edges of the kettle,there being a at its vertical side edges in a manner to make afluid-tight joint with the exterior surface of the kettle at oppositesides of the said joint 14?; the space between the strip and kettlebeing closed at the bottom so that said space Will hold filling orimpregnating substance the full height of said joint 14 riveting of thekettle fluid-tight.

The tank -12 is provided With a steam inpresent example of the inventionhas connected thereto a Supply pipe 29 having a branch pipe 30 leadingthereinto and constituting a steam outlet from-an evaporator 28 havingra heating coil 28, said evaporator 28 being generally of theform'usuallyemployed in evaporating Zinc-chlorid and the like and heremodi* fied and employed by me as a primary evaporator. In my use of theevaporator 28 I pi'ovide'the same with a closed top 28b hava sealing,

ing a s teain outlet -31 leading to' the atmoscisk valve 32 ispositioned between the suspended by a. link 34 from a lever 33 or thelike for operating the valve so that it may be moved tov constitute aclosure of either of isaid steam outlets. The pressure of the steamWithin the tank Will maintain the valve in the raised position closingthe outlet 31 but an)7 other suitable means mav be provided in additionfor positivelv holdint` the valve in the raised position. i

The kettle 14 is provided With a supply pipe 35 connected in practicewith a source of supply of the solution to be evaporated. Said pipeleads through the bottom 14a of to ,a suitable height above vthe liquidlevel of the kettle and. preferably has a downwardly inclined outlet 35afrom which the material escapes into the kettle Within 37 of the valvebeing here shown as having outlets 30. 31 and is i 'a bevel pinion 38,meshing ivitli a similar y pinion 39yon a vertical actuating rod 40pro-4 handle. From the bottom of the kettle'there vided ivithvanysuitable Wheel or other:

leads 'an outlet pipe 41 which pass'estli'rough the bottom' of the tub11 andfgis vprovided below the 'tub with a valve 42, the stem' 43 ofwhich' in the illustrated' 'form' has a bevel pinion 44 nieshingwith asimilar pinion 45 on a. vertioaloperating rod" 46'. Also, the kettle 14is provided. witha-l'vertieal 'overlowlpipe 47 which terminateslwithin'. the partition 19'atv the. f luid 'level- 'and 'extendsdownwardly through the`bottoni'g of rthe kettle andthrough the bottom oftheotub'yll 'to"a;wel1'48, saidoverflowpipe'. being approximatelythirty-four feet hi-gh in'praetioeso that' fluid overilowing into thewell 48 will not 'r-ise in responsefto thewaeuum have couplings '49interposedtherein so that the lowerportions of said pipes maybeuncoupled. -I provide a heating Coil or Coils .50 in the Itank 12, thatis to'say, in the steaiii space surrounding the kettle 14 beneath thelatter. One'endlof each kcoil vconnects bya valve' 51 with the outletpipe 41 within the tub 11, the stem 52 of said valve extendingadvantageously obliquely throughfthe stuiting box53 pr`ovided`oii"the"adjacent wall of thejtank '12,"the ternbeing. provided with a4rsuitable wheel olf-handle for Closing or. openingr the valve 51'..'The opposite end of a c oil 5 0 isi-in the form of a riser 54'e'x'--tending as .at'v55i`nto the side of'the kettle 14 to thusfoommunicatewith ythe spacel between the bodyfolffthe kettle and. the'partition 19.y l` 'To supply a puantityofhotfwaterv to the tub l111,' a l waterlinlet pipe 56.y extends up? wardly thrOugh'the bottom of saidtub and in`practice"i'nay. lbe 'connected with any' coiif venient-,s'ourceo Supplyto receive any hot water from otherl portions of the plantsuehfas'otherwise would be allowed to waste.v Additions t0 thewater inthe-tub 11 will result frointhe water of condensation from the Asteam inthe steamy jatiletsurrounfding the kettle; The pipe 56 is providedv`witl`i "a valve''4 tliesteni 58 of which is "provided with any suitable'operating means,f` hereshown a's'havinga bevel-pinionfthereonmeshingwith a similar pinion 60 onl a ver# 'ticaloperatii'igrod,61j'provided with a handwheeler the'likeifor turning. Theoperating rodsi 40", 46' 'and 61 terminate adjacent to. eaoh"=other'-for convenience vof operation and terminate adj aeentnt'o the outerends of th valve stems23 andA 52..

' n overflowf pipe 6211s provided iii-they tub'11 'and extendsdownwardly through the bottom thereof, 'said 4pipe rising withinthe tank..12 to the vdesiredwater level. Sur-r rounding` the major portion oftheoveryoiv pipe 62 fwithinthe' tank 12 .is asleeve 63 supported in anysuitablelmanner'and spaced from said pipe, the upperyend .of the saidsleere rising above the top of'said pipe', and

said sleevebeing open at the top and bottoni. "'The overflow pipe:621a'nd'its sleeve 63'a`re made large"enoughltvlfearryoif the water fromthe tub 11'afteritheawaterhas "lost its heat, and at the saine time'-Itliy'confstitute an air' vent -whei-.eby'airzmay pass out l of the'steani' j aoketforfintog'th'exsteam '.jaoket extending. higherthanjvsaid 'ioverllow pipe, it avill prevent the hotter.upperstrataotthewater in the tub 11'froin-passingfintothe overflow pipe whilepermittingv the cooler water nearer the bottom of the tub to furnish theoverflow into the vpipe throughthe lower end'of'the sleeveglAnadditional 'steam and airvent 64 may beprovided leadingr outwardly fromthe tank12 near thetop shown at theleft-oftheiftank in igfl, v

said vent pipe 64 havingfafsuitable Control- 'linfg valvey 64a.' vThelspao'efbetween 'the y.tub 'lfl'and the tank 12 willreceive'watervto thelevel ofthe water within-.theI tank; einde-fthe bottom of the tankisfopenfaind preferably rests directly' on thezbottom` 'of said tub,' sothat the 'water' inv saidl'lsp'aee sur-rounding lthe ylower" end ofthe'tankwill constitutea Seal oi-Vsteam 'trap;'preventing' escape .ofSteam or ingress of'aii'l-. The top28b'of prima-'ry' fitted` with twoportli'ghts o I 66 above one ofwhi'ch 'a lfs'tfiu'rcef'of*light may be"suspended or votherwise arranged' fto illuminate the interiorl of" said"'evaporator .F 'for taking observations 'throughv .thef'o'ther' ofsaidport lights. In the kettle'14- and'securedftojthe inner wall thereoffis' a curved defleetor y67 extending' aerossthespa'ee bevtween tli'eouter wall'orv shell off the `kettle '115 over partition 19andklownwardly'toward the center of the kettle', Th'efsteani 'inlet pipe29v` may .be provideddw'ith a'- valvelf68 above "the vbranch 30V leadingYfrom' thef'pri- ,maryievaporator 28. "The numeral "69in'di-x dates thestern ,of valveS` and said sterlis of suitable' length to extendffto apoint for .eoni'*enient operation by the attendant. The

several pipes' entering the bottom of the/tub 1'1 lhave lock nuts 7 0 orotlierfsiiitable "means to lprevent leakage. 'The'fvalve stem 5,2 isdetachably engaged with vthe `valve`51` in any suitable manner so thatsaidfstem mayl be withdrawn when the pipe connections of the kettle 14are disconnected for removal of-130 lower portion of the kettle forinsuring heat to the main body or mass of solution within the kettle. Aseries of collars or bands 72 preferably in the form of flat rings aredisposed edgewise on the exterior ofthe vacuum kettle 14 and serve tobrace and stiien the same so that the kettle ma)v the better resistatmospheric pressure thereon during the evaporating process and thus thecylindrical shape of the kettle is preserved. The lever 33 may besupported in anpT suitable manner. Itis here shown as fulcrumed on astandard 33a on the cover 28h of the primary evaporator.

In evaporating with my improved apparatus the valves 16, 36, 42 and 57are first closed and the condenser or air pump connected with theexhaust pipe 15 is putin operation to exhaust the air in the kettle 14to produce a partial vacuum therein. When the value or pressure ofthevacuum has reached the desired degree, the valve 36 is opened andzinc-chlorid or other solution to be evaporated is thus admitted to thekettle through thepipe 35 until the desired quantity is contained in thekettle. Said valve 36 isthen closed. The solution may be suppliedthrough the pipe 35 under the influence of the vacuum in the kettle orit may be positively forced through said pipe.

The valve 32 is now raised to close the atmospheric outlet 31 of theprimar)7 evaporator 28, thereb)r causing steam to pass through suppl;Ypipe 29 and inlet 27 into the space between the tank 12 and the kettle14. The valve 68 is also opened to allow exhaust steam from lthe steamengine or other apparatus of the plant to pass into the supply pipe 29lto the steam jacket or space surrounding the kettle. The valve 57 isalso opened. allowing hot water from any connected source of supplT topass through pipe 56 intotub-ll. Since the hotter water in tub 11 willtend'to remain near the top of v the bod v of water in said tub and thewater in giving up its heat to the coil or coils 50 will tend to settleto the bottom of the tub. the colder water pass upwardl)y into the lowerend of the sleeve 63 and upward therethrough to and into overiiowpipe 62and will dischargel through' the latter. The valve 51 isopened byturning its stem 52. the valve 12 remaining closed at this time.

The solution in the 'vacuum kettle 14 may V now flow downwardly throughthe pipe 41, through valve 51 into coils 50 and it will rise'in verticalpipes 54 until it has reached the level of the solution in the kettle14. The steam passing through pipe 29 into the steam jacket will drivethe air in the steam jacket out through the sleeve 63 and pipe. 62 tothe atmosphere and also through pipe 64 and through ,valve 64a to theatmosphere. The capacity of the vent pipe 64 will be regulated 1npractice by valve 64a. The steam will now heat the vacuum kettle andsince the latter is entirely surrounded b v steam except at the portlights 17. it will be abvious that all parts of the kettle will beexposed to the steam to receive the heat of the latter and thereby heatthe solution. The mass of the solution in the chamber outside of the'partition 19 at the lower end of said chamber is small as compared withthe mass or volume of the solution within the partition and thereforethe solution in said chamber will be heated lmore quickly. some heat.however, being acquired by the solution within the partition b v theheat applied to the bottom of the kettle and this being the case thesolution in the external chamsolution therein with the steam and thefoaming condition produced in the solution to be lighter than a similarcolumn of the solution without the steam and foaming. Finally. steam isgenerated so fast in the external chamber that the solution will rise bythe ebulition and pass over the top ofthe partition 19 and striking thecurved Vdeilector 67, itwill 1oe/directed' downwardly into the solutionat the approximate center of the kettle and a circulation ofthe solutionwill thus be set up from the kettle through the openings 20 to theexternal chamber and over the top of the partition 19. against thedelector 67 and be returned to the center of the kettle. The flowthroughthe openings ybei.' will boil and generate steam causing the 2Ois exactly regulated b v the valves 2.2.

The hot water inthe tub 11 and surrounding the coil or coils 50 as wellas the steam surrounding the vertically ranging'members 54 of the coilswill cause said coils to be heated which will heat the solution thereinand generate steam from the solution. Since the column of the solutionmixed with steam is lighter in weight than a. similar weight of thesolution alone. the solution will rise in the pipe or pipes-54 and will'pass out therefrom at the upper end intothe annular chamber at theexterior of the partition 19. mixing with 'the ysolution and boilingover the top ofthe partition andv downwardly to the center of the kettleso that a circulation is set up from the center of the kettle downwardlythrough the pipe 41 and through valve or valves 51 and coil or coils 50.The

. pipe 15.may be operated kunder the action of solution may be permittedto discharge -by j' will be vcontinually exhausted through the pipe andthe boiling or evaporating process continues untilvthe desired amount ofwater has been evaporated out of the solution or in other Woi'ds untilthe solution has lreached the desired density, whereupon valve 42 isopened and the solution in the vacuum` kettle is drawn out through pipe41 a pump if desired or the gravity by opening valve 16.

The condenser or pump connected with continuously, thus maintaining avacuum in the kettle 14 at the to discharge! through desired value, anda small stream of the solution may at the pass through the vvalve 36 tothe kettle and a regulated quantity of the solution allowed The boilingation and hence the evaporating process may be arrested at any time byjclosing the "valve 68 of the steam supply pip e 29 and causing thevalve 32 to close the steam outlet BD from the primary' evaporator 28thereby permitting steam from said primary evaporator to escape to theatmosphere, thecutting of of the steam from the steamjacket surroundingthe kettle 1.4 serving under these conditionsto stop the action` of thecondenser connected with exhaust pipe 15 by the increasing vacuumproduced j in the kettle in the absence of the generation of steamtherein as will readily be understood.' v

The steam passing to the upper portion ot the annular steam jacketsurrounding the kettle 14, that is.. to say` the steam rising betweentheIialeWi and the tank 12 will maintain suicient plume of steam at thatportion of the steam jacket and the steam be permitted te escape inrestricted quantity through tlievent pipe 64, the water ofcondensationafbeing permitted to pass downward between the baille 71 andthe tank to the tub 11.

Reverting Vto the circulation of the solution from the interior of thepartition 19 outwardly through openings 20 to the annular chambersurrounding said partition and upwardly at the outside of the latter.the result is obtained i-n addition to producing -a circulation that'theconversion of the water in vthe solution. into steam is promoted in theexternal chamber b v reason of the lesser mass of the solutioncontacting with the wall ot the kettle and b 'v reason of the greaterheating surface to which the solution in said chamber is exposed inrising therein. The

regulation of the flow outwardly through the openings 20 will be topermit a flow depending on -the rate of evaporation which in turn willdepend on the amount of steamsupplied to the steam jacket and the valueot the vacuum maintained in the kettle. Whenever it is desired to removethe kettle :stem permitting ;.top 13 of the tank same time be permittedto v valve 42 and pipe 41.

' end .with the -interior oft-.the yvesselat thethe nuts 7 0 onathepipes35,.y 41 'and '47 f are loosened, the couplingsin saidfpipesaredisconnected and the valvestei'n 52' of valve 51 is .disengaged'from4saidvzilve.y Provision is made also for disconnecting the valvejo stems23 and this maybe ldonennan'yfsi'iit-- able manner... In the'illustratedj'exampld ,the inner section 23@ has a socket23b' detach-.ably'receiving'the outer section of the' `valve 'y the latterto'bepulled-Joutng ward thus separating the yalvewstemffI-he 12 having.been removed by disconnecting the sections at the joiri'tfl, lthekettle with the,l secured portions '.'Qflthe pipesl 35, 415afnd-47A andthe Acoi-l orgcoilsO ,180 may. belifted `from. .the tanky12, thereby fftording access tobthefkettle andcoils or repair. s t.. M It ,ma bewelLto `state that,I .the ,abovedescribe@ apparatus has its 'specialuseful-*e5 ness in the;manufacture,olfyfber"infwhich large quantitiesof. zinc-.chlorid` are used fand are soaked from the; fiberl bywateiyvthesaine zinc-chlorid being .use dove'r and over.` ,if

I would state in conclusion:that'fwhilethe 90 illustrated ez'iampleconstitutes .1.a "practical embodiment ofamy invention, doI not limitmyself4 strictly toV74 the v{me'chaiiical:I rdetails hereinillustratedgsince manifestly ,the same can be considerably variedwithout depar-` 95 ture from the` spirit ofthe invention-as" deture andconnected with-.the bottomoiz-said vessel for the downflow of the` fluidcontents of the vessel and with said vesselaboif'el-.the bottom for thereturn of"thefluidftheretor- 2. An yevaporator 'including 'an 'evaporat-.,110 ing vessel having double side Walls;forniing a chambersurrounding'` the; innerfivall; aiidin 1L-f.

communication yv'iththe interior ofthe vessel below the liquidlevelthelfeo andfiibve said liquid level, a coil: below and outsideotsaid vessel, and means to siibjectlsaidjco' "to heat, said-coilbeing-'in commuhicjat'ont ne i tom of the latten vand incommunieati'oiilit its other end withqsaid.lchainberfabti vethe bottomthereot` to'promte circulationo' the liquid being evaporated. 31; A fz,

3. An evaporator includi1ig"a'tubf, af .fta-nk having an fopen bottom,aml'supported with its lower-end approximately atftlie bot: .125:

tom ot the tub. and a closed evaporatiiig vvessel within the tank; saidtubbeing` adapted to hold a heating liquid and being spaced from'thejtank scf-that theliquid in the tub y will forni a seal forthelower endof the tank to prevent egress of steam between the tank and tub andprevent ingress, of air to the tank.l

'4. An evaporatorl including a tub, a tank having an open bottom andsupported with its lower end approximately at the bottom ot' the' tub,and a closed evaporating vessel withinthe tank, said tub being hold aheatin liquid and being spaced from the tank so t at the liquid in theltub Lwill form a seal for -thelower end of the tank to revent of steambetween Athe tank an tub anv yprevent ingress ofair to the tankrtogetherwith anoverflow pipe leading from the tub within the tank and detertheheight of liquid in the tub and in the space between theftub and tank.

'5. An evaporating apparatus including a tub, a tank supported in saidtub,'said tub being Iadapted to hold a ybody of heating liquid, anevaporating vessel supported with- 1n said tank and spaced therefrom 'toproduce a .steam jacket surrounding said vessel,

means to supply steam to said space, anv

overflow pipe leading from the tub within the tank, and a said overflowpipe and extending above the same said guard being spaced from theoverflow pipe and from the bottom of the tub and being open at the topand bottom.

.6. An evaporating apparatus including a tub, an open-bottom tanksupported'on the bottom of the tub, an evaporating vessel within saidtank-and spaced therefrom to -provide a steam jacket surrounding thevesfs'e'l, said` tank having a steam inlet leading to said space andadapted to be connected with .a source of steam supply, said tub .beingadapted to hold hot water and. to receive the water ofcondensation fromthe steam in the steam jacket, and an overfiow pipe"leading from "saidtub to permit the overow of i said' water.

7. An V evaptn'at'ing apparatus including a tub, an open-bottom tanksupported on the bottom of the tub, an evaporating vesselwithin'said-tank and spaced therefrom to provide a steam jacketsurrouding the vessel, said tank having a steam inlet leading to saidspace and adapted to be connected with a source of steam supply, saidtub being adapted to hold hot water and to receive the water ofcondensation from the steam in the steam jacket, and an overflow pipeleading from said tub to permit the overfiow of sald water; togetherwith means surround- 4ingsaid overflow pipe and preventing direct'entrance-,of water thereto from the hotter f eo,

strata of water but permitting entrance 'to said pipe of water from apolnt below the "8. ,An evaporator including ar evaporating vesselhaving double walls at the Vsides spaced from each other to provide achamber'therebetween, said chamber being open adapted toardsleevesurrounding the at the 'top to communicate with the vessel withinthe inner wall, and being in communication yalso ywith the interior ofthe vessel'below the liquid level thereof, and valves controlling thelast-mentioned communica- 'tion and operable from the exterior of theevaporator.

9. An evaporator including an evaporating vessel, a structuresurrounding said vessel and spaced therefrom to form a steam jackettherebetween, a discharge pipe `lead- `ing from said vessel at thebottom to carry off `the solution after treatment thereof, a valvecontrolling said discharge pipe, a coil between the bottom of the vesseland the bottom of said structure and connected at one end with saiddischarge pipe, and a valve, controlling communication between said coiland the discharge pipe, said coil having connection at the opposite endwith said vessel above the bottom thereof.

10. An evaporator including an evaporating vessel, a structure in whichsaid vessel is supported, and spaced therefrom to provide a spacetherebetween, an inletto said structure to conduct a heating mediumthereinto, an inlet pipe leading through the bottom of said structureand through the bottom of said vessel, to supply a charge of solution tosaid vessel, a discharge pipe leading from said vessel at the bottomthrough the bottom of said structure, said pipes having detachablecouplings interposed therein, below the bottom of said structure, a coilin said structure beneath said vessel, said coil being connected at oneend of said discharge pipe and connected at its opposite end with saidvessel above the bottom thereof, a valve controlling communicationbetween the discharge pipe andsaid coil, and a valve stem detachablyengaging said valve and controllable from thev exterior of saidstructure for operating the valve or detaching the stem from the valve,-together with a removable top on said structure permitting the removalof said vessel upon disconnection of said couplings and said valve stem.

ll. An evaporator including an evaporating vessel surrounded by a steamspace, a primary evaporator having a steam outlet communicating withsaid space,-a steam outlet to the atmosphere from said primaryevaporator and positioned in the top thereof. said second outlet beingseparated from and in alinement with the first-mentioned steam outlet`and a valve disposed in said primary evaporator between said steamoutlets. and

adapted to be moved axially to -a posit-ionl 'tub with its lower endbelow the top of said tub, a closed evaporating ketttle within said leov tank' and spaced therefrom to form a steam maintain in the tub a Wateryseal for the jacket surrounding said kettle, means to tank.

maintain a volume of steam in said jacket, THOMAS M. PUSEY. said tubbeing adapted to hold Water of conllitnesses :4

l densation resulting from the steam, and an Ensn; C. WILEY,` overowpipe leading from said tub at the JOHN C. PRATT,

bottom and rising therein to a height to C. G. HAZLETT.

